noun
honorarium
ahn-uh-RAIR-ee-um/ˌɑːnəˈreriəm/
A payment for professional services for which no fee is set.
The college offers its guest speaker an honorarium rather than a set fee.

Etymology
An honorarium is literally an honorary gift: a payment framed as a mark of esteem for someone's services. That idea underlies its use for professional work without a set fee.
In context
not in a position to pay a speaker's fee or honorarium
More examples
- Although she charges nothing for the lecture, she accepts an honorarium.
- The museum gives the visiting historian a modest honorarium.
- Guest lecturers receive honoraria and reimbursement for travel expenses.
Forms
honorarium · honorariums · honoraria